JPS62137237A - Controller for continuously variable transmission - Google Patents

Abstract

PURPOSE:To prevent shocks in turning on a clutch by providing a means for detecting the actual rotational frequency of an engine which is made a desired control value when an accelerator pedal is pedalled in travelling within N range. CONSTITUTION:When a throttle is not completely closed and vehicle speed exceeds a predetermined value, a desired control rotational speed of turbine following up the practical rotational speed of turbine is determined to control the change gear ratio on the basis of said desired control rotational speed. Thus, the change gear ratio is controlled such that the rotational speed at the output side of a clutch 40 for advance always coincides with the rotational speed at the input side of the clutch 40 for advance. Thus, when D range is changed over selectively to N range, the input and output sides of clutch 40 are held under the synchronized condition. When D range is again selected under such condition, the clutch 40 is turned on without producing shocks since the clutch 40 has the output and input sides rotated synchronously.

Description

[Detailed description of the invention] (b) Industrial application fields The present invention relates to a control device for a continuously variable transmission.

(b) Conventional technology As a conventional continuously variable transmission control device, Japanese Patent Application Laid-Open No. 58-1
There is one shown in No. 80863. According to this, D
, L, N, etc., and then determines a desired gear ratio command signal according to conditions such as vehicle speed and throttle opening, and based on this, a gear change actuator such as a gear change motor. It's like you want to control it.

For example, the shift pattern in the D range is such that the engine is always operated at the minimum fuel consumption rate,
Furthermore, in the L range, a shift pattern is set in which the driving force is larger and the engine braking effect is greater than in the D range. In the N range, the gear ratio is always controlled to be in the maximum gear ratio state that can be obtained with the continuously variable transmission. This is to enable the vehicle to start at the maximum gear ratio immediately after selecting a driving range such as the D range from the N range to start driving.

(c) Problems to be solved by the invention However, with such conventional control devices for continuously variable transmissions,
In the N range, the gear ratio is always controlled to be at the maximum, so for example, when driving in the D range, the N
If you select range and then return to D range, N
While the gear ratio is selected in range, the gear ratio is at its maximum, and when you return to D range, engine braking is applied suddenly, resulting in a large shock, which affects the driving feeling. This can worsen and in some cases cause the vehicle to spin or the engine to overrun.

In order to solve the above-mentioned problems, the present applicant proposed in Japanese Patent Application No. 59-87788 that when the vehicle is running at a speed higher than a predetermined speed, the same gear ratio as in the D range is applied when the vehicle is in the N range. I disclosed what I had ordered. As a result, D
When selecting from range to N range to D range, sudden gear changes are prevented and the D range is smoothly changed.
It is possible to return to the range running state.

However, even when the above control is performed, if the throttle opening is made larger than fully closed while the engine speed is increased while the D range is selected from the N range, the engine rotation speed will be increased when the next time the D range is selected. Since the control state of the automatic transmission and the rotational state of the engine do not match, the clutch is engaged with a large difference in rotational speed between the input end and the output end of the forward clutch, resulting in a large engagement. generate shock. This fastening shock is not only an unpleasant shock for the occupants, but also causes the V-belt to slip due to excessive torque fluctuations, potentially damaging the V-belt, pulleys, etc. The present invention aims to solve these problems.

(d) Means for solving the problem The present invention controls the gear ratio so as to synchronize the input end rotation speed and the output side rotation speed of the forward clutch when the throttle is opened in the N range. By doing so, the above problems are solved. That is, the control device for a continuously variable transmission according to the present invention includes a neutral detecting means for detecting that the select lever is in the neutral position, a fully closed throttle detecting means for detecting that the throttle is in a fully closed operating state, and a fully closed throttle detecting means for detecting that the select lever is in the neutral position. A vehicle speed detection means for detecting the actual engine rotation speed or an actual rotation speed detection means for detecting the actual turbine rotation speed, and the select lever is in the neutral position, the vehicle speed is a predetermined value or more, and the throttle is not in a fully closed operation state. In this case, a neutral speed change control means is provided for setting the actual engine rotational speed or the actual turbine rotational speed as the control target value.

(e) Operation When the select lever is set to the neutral position and the throttle is opened and the vehicle is traveling at a predetermined speed or higher, the actual engine rotation speed or actual turbine rotation speed is set as the control target value by the neutral speed change control means. The gear ratio is controlled. Therefore, the rotational speeds of the input end and the output side of the clutch are controlled to always match or almost match. Therefore, when the D range is selected from this state, the clutch is engaged without any rotational fluctuation, and the D range running state is smoothly achieved without generating a shock.

(F) Embodiment FIG. 2 shows a power transmission mechanism of a continuously variable transmission. This continuously variable transmission has a fluid coupling 12 (fluid transmission device), a forward/reverse switching mechanism 15, a V-belt type continuously variable transmission mechanism 29, a differential device 56, etc., and includes an output shaft 10a of the engine 10.
output shafts 66 and 6 at a predetermined gear ratio and rotation direction.
8 can be transmitted. This continuously variable transmission includes a fluid coupling 12 (including a lock-up oil chamber 12a, a pump impeller 12b, a turbine runner 12c, etc.), a rotating shaft 13, a drive shaft 14, a forward/reverse switching mechanism 15,
Drive pulley 16 (fixed conical plate 18, drive pulley cylinder chamber 20 (chamber 20a, chamber 20b), movable conical plate 22,
(consisting of groove 22a, etc.), planetary gear mechanism 17 (consisting of sun gear 19, pinion gear 21, pinion gear 23, pinion carrier 25, internal gear 27, etc.),
Belt 24, driven pulley 26 (consisting of fixed conical plate 30, driven pulley cylinder chamber 32, movable conical plate 34, etc.)
, driven shaft 28, forward clutch 40, drive gear 46, idler gear 48, reverse brake 50, idler shaft 52
．． It is composed of a pinion gear 54, a final gear 44, a pinion gear 58, a pinion gear 6-0, a side gear 62, a sight gear 64, an output shaft 66, an output shaft 68, etc., but a detailed explanation thereof will be omitted. The structure of the portions whose explanations are omitted are described in Japanese Patent Application No. 59-226706 filed by the present applicant.

FIG. 3 shows the hydraulic control system for the continuously variable transmission. This hydraulic control device includes an oil pump 101 and a line pressure regulating valve 102.
, manual valve 104, speed change control valve 106, adjustment pressure switching valve 108, speed change motor (step motor) 110, speed change operation mechanism 112, throttle valve 114, constant pressure pressure adjustment valve 11
6, a solenoid valve 118, a coupling pressure regulating valve 120, a lock apple J control valve 122, etc., which are connected to each other as shown in the figure, and a forward clutch 4.
0, reverse brake 50, fluid coupling 12,
The lock-up oil chamber 12a, the driving pulley cylinder chamber 20, and the driven pulley cylinder chamber 32 are also connected as shown. A detailed explanation of these valves and the like will be omitted. For the parts omitted from explanation, please refer to the above-mentioned patent application 1986-2.
No. 26706. In addition, each reference numeral in FIG. 3 indicates the following members. Pinion gear 110a, tank 130, strainer 131, oil passage 132, relief valve 133, valve hole 134, boat 134aNe, spool 1
36, land 136a%b, oil passage 138, one-way orifice 139, oil passage 140, oil passage 142, one-way orifice 143, valve hole 146, boat 146aNg, spool 148, lands 148a to e, sleeve 150, spring 152, spring 154, pressing member 158,
Oil passage 164, oil passage 165, orifice 166, orifice 170, valve hole 172, boat 172a-e, spool 174, lands 174a-C, spring 175, oil passage 176, orifice 177, lever! 78, oil road 179
, bottle 181, rod 182, land 182aNb, rack 182c, bottle 183, bottle 185, valve hole 186,
Boat 186aA-d, oil path 188, oil path 189, oil path 190, valve hole 192, boat 192aNg, spool 1
94, land 194a=e, negative pressure diaphragm 198,
Orifice 199, Orifice 202, Orifice 20
3. Valve hole 204, boat 204aNe, spool 206
, land 206a Nb, spring 208, oil passage 20
9, filter 211, orifice 216, boat 22
2, solenoid 224, plunger 224a, spring 225, valve hole 230, boat 230 a Ne, spool 232, runt 232a-b, spring 234,
Oil passage 235, orifice 236, valve hole 240, boat 2
40a to h5 spool 242, land 242aNe, oil path 243, oil path 245, orifice 246, orifice 247, orifice 248, orifice 249, choke type throttle valve 250, relief pulp 251, choke type throttle valve 252, pressure holding valve 253, oil Road 254, Cooler 2
56, Taller pressure holding valve 258, orifice 259, changeover detection switch 278. FIG. The speed change control device 300 includes an input interface 311, a reference pulse generator 312, and a CPU (central processing unit) 313.
, ROM (read only memory) 314, RAM (
random access memory) 315 and an output interface 316, which are connected to an address bus 319.
and data bus 320. This shift control device 300 includes an engine rotation speed sensor 30.
1. Vehicle speed sensor 302, throttle opening sensor 30
3. Shift position switch 304, turbine rotation speed sensor 305, engine coolant temperature sensor 306,
Pattern selection switch 323, brake sensor 307
and the signal from the changeover detection switch 298 is transmitted directly or to the waveform shapers 308, 309 and 322, and the AD converter 31.
0, while the width device 317 and the line 317a
A signal is output to the step motor 110 through -d,
Further, signals are also output to the solenoid 224, but a detailed explanation of these will be omitted. The structure of the parts whose explanation is omitted can be found in the above-mentioned Japanese Patent Application No. 59-2267.
It is described in No. 06.

5 and 6 show details of control performed by the speed change control device 300. Of these, the complete engagement control of the clutch by controlling the solenoid 224 and the lock-up control of the fluid coupling 12 are the same as those described in the above-mentioned Japanese Patent Application No. 59-226706, and therefore their explanation will be omitted.

First, the shift position is read from the shift position switch 304 (step 502), and then it is determined whether it is in the driving range, that is, D, L, or N range (step 504), and if it is not in the driving position, that is, in the N range or In the case of P range, the duty ratio of the solenoid 224 is set to 0 to release the lock-up clutch (506), and then it is determined whether the idle switch is on (507); if the idle switch is not on, That is, when the throttle is not fully closed, the current vehicle speed Vs is set to a predetermined vehicle speed V+C, for example, 10k
m/h) to determine whether it is larger than 509
), in the case of V s > V +, the current actual turbine rotation speed Nt is set to the control target turbine rotation speed Nt (step 511). Next, the target step motor pulse number 20 is searched based on the control target turbine rotational speed Nto (step 513). Then step 63 in FIG.
Go to 0. Note that if the throttle is fully closed in step 507 or if Vs≦v1 in step 509, the process advances to step 626. The controls after step 630 and other controls are the same as those described in the aforementioned Japanese Patent Application No. 1983-Shiba No. 26706, so their explanation will be omitted.

In the end, the control routine described above will perform the following control. That is, in the case of D, L, and N ranges, shift patterns are searched for each range (steps 626, 628, and 640). In the case of N or P range, there are two cases depending on the operating state. That is, when the throttle is fully closed or when the vehicle speed is V or less, the gear ratio searched based on the D range shift pattern is commanded. For example, while driving in D range,
When the range is selected and the throttle is fully closed, the forward clutch 40 is released, resulting in a neutral state, but ■
The belt-type continuously variable transmission mechanism 29 itself is maintained at the normal gear ratio in the D range, and when the D range is selected again, the belt type continuously variable transmission mechanism 29 returns to the running state in the D range without any rotational fluctuation. On the other hand, when the throttle is not fully closed and the vehicle speed is higher than Vl, the control target turbine rotation speed Nto is determined following the actual turbine rotation speed Nt, and the gear ratio is controlled based on this. Therefore, the rotational speed of the drive pulley 16, that is, the rotational speed of the output side of the forward clutch 40, is the actual rotational speed of the turbine 12c, that is, the rotational speed of the forward clutch 40.
The gear ratio is controlled so that it always matches the rotational speed of the zero input end. Therefore, as in the above case, from D range to N
When the range is selected, the speed is changed so that the input end and the output side of the forward clutch 40 are always kept in a synchronized state. When the D range is selected again in this state, the input and output sides of the prefectural road clutch 40 are rotating synchronously, so 1. is concluded without causing any shock. Therefore, no shock occurs, and no slipping of the V-belt occurs.

Note that when the vehicle speed Vs is below V1, the D range shift pattern is searched for in the N and P ranges as well, and the gear ratio becomes the maximum state. Therefore, for example, when selecting from the N range to the D range and starting immediately The vehicle immediately starts moving at the maximum gear ratio.

In the above embodiment, the turbine rotational speed was controlled in steps 511 and 513, but the control is performed approximately on the engine rotational speed, ignoring the input/output rotational difference of the fluid transmission device. You can also do it.

(G) As described in detail, according to the present invention, when the accelerator pedal is pressed while driving in the N range, the actual turbine rotational speed (or actual engine rotational speed) is controlled to the target turbine. Since the speed change control of the continuously variable transmission is performed based on the engine rotation speed (or control target engine rotation speed), it is possible to almost eliminate the clutch engagement shock when the D range is selected afterward, and the driving speed is improved. The feeling can be improved and slippage of the V-belt can be prevented.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the relationship between the constituent elements of the present invention, Fig. 2 is a diagram showing the power transmission mechanism of the continuously variable transmission, Fig. 3 is a diagram showing the hydraulic control device of the continuously variable transmission, and Fig. 4 is a diagram showing the hydraulic control device of the continuously variable transmission. This figure shows a speed change control device for a continuously variable transmission, and FIGS. 5 and 6 are diagrams showing a control routine of the speed change control device.

Claims (1)

[Scope of Claims] A speed change actuator is operated so that a control target value is realized for a speed change ratio of a continuously variable transmission in which the rotation of a turbine of a fluid transmission device is input to a drive pulley via a forward/reverse switching mechanism. In a control device for a continuously variable transmission, the control device includes a neutral detection means for detecting that the select lever is in the neutral position, a fully closed throttle detection means for detecting that the throttle is in a fully closed operating state, and a vehicle speed detection means. and an actual rotation speed detection means that detects the actual engine rotation speed or the actual turbine rotation speed, and when the select lever is in the neutral position, the vehicle speed is a predetermined value or more, and the throttle is not in a fully closed operating state. 1. A control device for a continuously variable transmission, comprising: a neutral speed change control means for setting an actual engine rotation speed or an actual turbine rotation speed as a control target value.